Display screen or portion thereof with transitional graphical user interface



FIG. 1 is a first image in a sequence for a display screen or portionthereof with transitional graphical user interface showing my newdesign;

FIG. 2 is a second image thereof;

FIG. 3 is a third image thereof;

FIG. 4 is a fourth image thereof;

FIG. 5 is a fifth image thereof;

FIG. 6 is a sixth image thereof;

FIG. 7 is a seventh image thereof; and,

FIG. 8 is an eighth image thereof.

The appearance of the animated user interface sequentially transitionsbetween the images shown in FIGS. 1-8. The process or period in whichone image transitions to another forms no part of the claimed design.The broken lines show a display screen or portion thereof and form nopart of the claimed design.

CLAIM The ornamental design for a display screen or portion thereof withtransitional graphical user interface, as shown and described.